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Sound stuttering after Mountain Lion install

Dear community,


after having installed OSX Mountain Lion my sound startet stuttering whenever there is rapid movement on my screen.

This includes e.g. window movement, scrolling through image loaded websites or video playback (flash player, quicktime).

A restart didn't help. I'm using stereo output, not digital.


I have connected a second monitor but the problem persists after disconnecting it. Movement on the second monitor also causes the sound to stutter.

My GPU Diode temperature is at 85°C (there is some bug that keeps the GPU under load while a second monitor is connected AFAIK), but I guess it was the same under Snow Leopard.


In Snow Leopard the sound output was always perfect even under heavy load or heavy HDD I/O.


Any ideas?

iMac (27-inch Mid 2011), OS X Mountain Lion

Posted on Jul 28, 2012 5:48 AM

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Posted on Jul 28, 2012 3:22 PM

I am also having this issue as well.


I opened Activity Monitor and noticed that during the stuttering, coreaudiod jumps in CPU usage, often past 5%. I have also noticed graphics lag when this occurs if I'm doing something like watching full-screen video or gaming.


I'm currently experiencing this on mid 2011 iMac 27" as well as a 24" iMac 2009 model I use at work.

1,223 replies

Aug 20, 2012 10:39 AM in response to tttxx

I am also badly bitten by the stutter bug. I took arecording of it to send to Apple care sometime. In the mean time I was streaming using nicecast into Secondlife and listening to my music is Secondlife. The sound started its stuttering. Leaving the mac alone, I connected to my stream on my iPhone and the music I was streaming was perfect. I then played the music over airplay to a local loudespeaker from the iPhone. The stuttering was still on the mac however.


From this I can only conclude the problem lies in the way OS X is deliverng the sound after decoding to the audio system. Nice cast captures the music after the pogram, iTunes, Djay whatever, has decoded the media info but before it gets delivered to the audio device.


I think 😉


I get the stuttering on the interal loudspeakers, a USB sound card/headphone and built in headphones.

Aug 22, 2012 2:41 PM in response to tttxx

Found a fix after spending an entire evening trying to fix this... (I'm on a retina macbook pro, so I'm not sure if this option is on other macs)


Go to System Preferences

Energy Saver

Uncheck 'Automatic Graphics Switching'


No more sound stuttering/crackling.


I'm guessing the issue lies in the integrated video card. When using the Nvidia (by unchecking the above), the problem completely disappears. However, still isn't acceptable as a fix to me as my battery life worsens as I'm always running off the Nvidia card in OSX. Btw, this sound/stutter issue is completely nonexistant in Bootcamp. So it 100% is a software related bug in Mountain Lion.

Aug 22, 2012 6:39 PM in response to Community User

rxghost12 wrote:


I'm guessing the issue lies in the integrated video card. When using the Nvidia (by unchecking the above), the problem completely disappears.


Looks like we got the issue isolated somewhat.


I'm on a 13" Macbook Pro and so only have an intergrated video card.


Maybe it's a video card driver problem. Let hope Apple can fix this soon.

Aug 22, 2012 8:02 PM in response to pepper_chico

yea def looks like it's an issue with the integrated graphics driver.


Anyone who has a retina display or who has the ability to switch between two graphics cards (between integrated and nvidia) on their macbook, etc. Please test out just the nvidia alone. I'm sure that will cure the crackling, stutter effect for the audio. I'm guessing there's some bug with the integrated graphics driver within mountain lion causing the audio issues.

Aug 23, 2012 9:50 AM in response to Lvivske

Anyone try out the new 10.8.1 patch?? So far I'm not getting any popping/crackling/buzzing... but it does come in randomly so we'll see... hopefully this fixed the issue..

Sound stuttering after Mountain Lion install

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